The present invention generally relates to a hot water feeding arrangement which utilizes entry and emission of heat following reversible bonding and dissociation between metal hydrides and hydrogen gas and more particularly, to a heat pump hot water supply unit of energy saving type with a high heat utilizing efficiency which is simple in construction and compact in size, and can be readily employed for any fields utilizing heat in general such as domestic heating or industrial boilers, etc. as well as for hot water feeding.
Conventionally, various hot water supply units which utilize electric power, gas, petroleum or the like as a fuel, have been widely put into practical applications, for example, in the form of a boiler for feeding hot water at about 80.degree. C., a boiler for heating rooms, and a boiler for power generation, etc. according to the end uses and fuels to be employed. Although these supply units are comparatively cheap and convenient to use, a further improvement of the efficiency thereof will particularly be required henceforth in the age where prices of fuel are generally high. In connection with the above, in the prior art techniques, for example, only about 90% of heat imparted by combustion, etc. is utilized as an effective heat amount, without exceeding 100% in any case.
On the other hand, heat pump techniques such as the motor compression type, absorption type, etc. have also made progress for actual utilization, and if such techniques as referred to above are employed, it becomes possible to increase the effective heat amount by obtaining heat from heat sources at comparatively low temperatures such as the atmospheric heat, heat of the earth, etc. and raising the temperature thereof to a comparatively high level, and thus, the above efficiency may be raised over 100% for the actual application. However, since the heat pumps of the motor compression type and engine compression type, or heat pumps of a continuous absorption type as referred to earlier are arranged to circulate a heating medium or absorbing liquid, there are still such disadvantages that pumps and control units employed therein complicate the unit, while noises are undesirably produced in the compression type.